Thermally responsive switch



Filed April 16, 1962 INVENTOR.

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United States Patent Oftice 3,127,489 Patented Mar. 31, 1964 3,127,489 THERMALLY RESPONSIVE SWITCH Frank J. Wallace, Chicago, Ill. (1159 Highland, Oak Park, Ill.) Filed Apr. 16, 1962, Ser. No. 187,653 Claims. (Cl. 20d-113) This invention appertains to automatic electrical switches and more specifically to self-actuating intermitting switches comprising a thermally expansible element for actuating a snap action contact.

A general object of the invention is to provide a novel relay which is rugged and shock-resistant.

A further object of the invention is to provide a sensitive relay, which is of fairly simple construction and which eliminates critical tolerances such as normally complicate manufacture and add considerable expense to the unit.

Another object of the invention is to provide a novel thermal switch with a snap action contact, the position of which is controlled by the thermal element, the contact being disposed in laterally spaced side by side relation with a leaf spring return and tensioning standard and the space being bridged by a U-shaped toggle spring link which functions to move the contact to open position upon the spring standard being flexed by the thermal element to a position disposing the toggle link to open the contact.

A further object of the invention is to devise a novel anchor for the thermal element which greatly improves the longevity of the element and its connections.

These and other objects and advantages inherent in and encompassed by the invention will become more readily apparent from the specification and the drawings, wherein:

FIGURE 1 is an axial sectional view of the relay taken substantially on line 1-1 of FIGURE 4 with the contacts closed;

FIGURE 2 is a sectional view taken substantially on line 2--2 of FIGURE 4 with the contacts open;

FIGURE 3 is a perspective View; and

FIGURE 4 is a cross-sectional view taken generally on line 4--4 of FIGURE l.

Description of the Invention Describing the invention in detail and having particular reference to the drawings, there is shown a relay or flasher switch generally indicated 2 which includes a base 3, a casing 4 of any suitable material mounted thereon, prongs 5, 5 and 6 extending below the base 3, and having portions extending above the base 3 which is formed of any suitable dielectric material.

The prongs 5, 5 are interconnected at their upper ends above the base 3 to a bracket 1t) which has a base ilange 11 suitably fastened to the base 3 as by rivets 12. A support flange 13 projects upwardly or outwardly from flange 11 generally normal to the base 3 and mounts the inner or lower end of a flat, U-shaped steel spring combination contact and biasing element generally designated 15 which comprisesA a bight portion 15 with a flange 16 beneath bracket flange 11 and secured therewith by the rivet 12.

The element 15 comprises a contact leg 16 with a contact nub 17. Leg 16 laterally opposes the biasing leg 19, said leg 16 comprising a notch 2d which admits one hook end 21 of a U-shaped toggle spring link 2v2 which is oriented in a plane transverse to the flat strips 16 and 19 and has its opposite hook end 23 projected through an aperture 24 in the upper end of the tension leg 19 which in the contact position of the leg 16 leans at one side of dead center position as shown in FIP- URE 1.

The upper free end of leg 1d is suitably secured to a thermoelectrc wire 25 which has a downwardly extending length 26 which terminates in one end of a helical portion 27 which is wrapped about a tubular or cylindrical glass bearing 28 which is mounted on a journal stud 3d extending generally normal to the plane of leg or contact arm 31 which extends generally parallel to contact 16 in opposing relation thereto, said contact 31 having a contact point 32 adapted to be engaged by contact 17 in the closed position of the switch. The helical portion 27 has its inner end connected to the lower end of a length 29 of the wire 25 which is connected at its upper end to anchor 33 at the upper end of the contact arm 31. In the expansion and contraction of the element 25 the bearing 28 obtains a rotary motion to accommodate thermal creep of the wire.

The lower or inner end of the arm 31 is provided with a l'lange 35 which seats atop the base and is secured by rivet 56 thereto, and ange 35, and merges into the prong 6.

The asher switch is embodied in any conventional circuit and upon the current passing through the contacts the parts assurne the position of FIGURE 1 and upon cooling of the wire 25 and contraction thereof, the arm 19 is pulled to the position of FIGURE 2 opening the contacts 17, 32 by moving arm 16 away from arm 31 by means of the action of the toggle link 22. Movement of arm 16 is limited by the stop 37 which is formed on arm 31 and has a dielectric coated abutment portion 38 engageable behind arm 16.

In the structure herein disclosed, it will be seen that the parts are of simple construction, do not require critical setting and operate efficiently Without the necessity of critical adjustment. Furthermore the longevity of the unit is improved in providing more yield in the thermal element particularly in the extensive length and accommodating creep thereof to obtain extensive movement of the spring part 19. The extensive movement of arm 19 obviates the necessity of precise settings between the contacts or critical adjustment or spacing of the contact arms, etc.

Having described a preferred embodiment of the invention, it will be understood that various changes will become readily apparent within the spirit of the invention to those skilled in the art and which are intended to be covered by the claims appended hereto.

I claim:

1. ln a switching device, a base, first and second opposing contact elements thereon, a biasing member `on the base sprung transversely of one of the contact elements and spaced laterally therefrom, a toggle link comprising a U-shaped spring transversely deflected between and pivoted at spaced points to said one element and member and responsive to exing of said biasing member operative to move said one element into and out of contact with the other element pursuant to transverse back and forth deflection of said member with attendant movement of the point of connection of the spring to said member past dead center positions with respect to the other point, and a thermoelectric wire connected at one end to said member and at the other end to the other of said elements, and a creep accommodating anchorage means fixed with respect to the base and comprising a bearing rotatably supporting said wire intermediate the ends thereof.

2. In a switching device, a support, a pair of elongated cooperative contacts mounted in side by side relation at one end on the support, one of the contacts being relatively rigid and the other contact being relatively exible, an elongated exible biasing arm mounted at one end on the support and laterally odset from the one contact, a flexible U-shaped toggle link extending transversely of the arm and one contact and bridging the space therebetween and rockably connected at opposite ends to the one contact and arm respectively, said arm transversely movable for positioning the toggle in either of two overcenter positions to thus move said one contact through the toggle from make to break positions and vice versa, and a thermoelectric Wire having one end connected to the other end of the arm and other end of the other contact and having lengths from its ends to an intermediate portion thereof convergingly arranged, and an anchor on the support having said intermediate portion of the wire wrapped thereon and holding said lengths of Wire in tension between the ends thereof and the said intermediate portion said wire and anchor having rolling contact with each other.

3. The invention according to claim 2 and said intermediate portion comprising a coil.

4. The invention according to claim 3 and saidanchor comprising a roller within the coil rotatably mountedon the support.

5. In a flasher switch, a base, a pair of Contact members having inner ends secured to the base, Contact points on the outer ends of the members, a ilexible arm at one side of the contact members xed' at its inner end to the base, a toggle link extending transversely of and connected between the outer ends of the arm and one contact member, an anchor adjacent to the base and xed with respect thereto, a thermoelectric wire drawn taut from the outer end of the arm under the anchor and to the outer end of the other Contact, and said wire having au intermediate coil portion, and said anchor having a bearing rotatably supporting said coil portion for coiling and uncoiling movements thereon.

ReferencesCited in the file of this patent UNITED STATES PATENTS 1,923,509 Rozumek Aug. 22, 1933 2,641,666 Sitzer June 9, 1953 2,672,563 Boddy Mar. 16, 1954 

1. IN A SWITCHING DEVICE, A BASE, FIRST AND SECOND OPPOSING CONTACT ELEMENTS THEREON, A BIASING MEMBER ON THE BASE SPRUNG TRANSVERSELY OF ONE OF THE CONTACT ELEMENTS AND SPACED LATERALLY THEREFROM, A TOGGLE LINK COMPRISING A U-SHAPED SPRING TRANSVERSELY DEFLECTED BETWEEN AND PIVOTED AT SPACED POINTS TO SAID ONE ELEMENT AND MEMBER AND RESPONSIVE TO FLEXING OF SAID BIASING MEMBER OPERATIVE TO MOVE SAID ONE ELEMENT INTO AND OUT OF CONTACT WITH THE OTHER ELEMENT PURSUANT TO TRANSVERSE BACK AND FORTH DEFLECTION OF SAID MEMBER WITH ATTENDANT MOVEMENT OF THE POINT OF CONNECTION OF THE SPRING TO SAID MEMBER PAST DEAD CENTER POSITIONS WITH RESPECT TO THE OTHER POINT, AND A THERMOELECTRIC WIRE CONNECTED AT ONE END TO SAID MEMBER AND AT THE OTHER END TO THE OTHER OF SAID ELEMENTS, AND A CREEP ACCOMMODATING ANCHORAGE MEANS FIXED WITH RESPECT TO THE BASE AND COMPRISING A BEARING ROTATABLY SUPPORTING SAID WIRE INTERMEDIATE THE ENDS THEREOF. 